Model Output Discussion 1200 hrs 30/09/14

[Polar Maritime]

A cool/cold run from today's 6z for the start of November, With the Jet pushing a little further South. Bringing bout's of unsettled Polar Maritime air over the UK from the N/W. Frosts will become more of a feature as we move into the new Month, With a more Autumnal/seasonal feel to things than of recent weeks.

 

Edited October 25, 2014 by Polar Maritime

[Summer Sun]

With the clock change at 2am tomorrow this is just to remind folks that the models will be out 1 hour earlier from tomorrow, so for the 12z's GFS will start around 15:30 with ECM running from 18:00 to 19:00

[Cloud 10]

With the clock change at 2am tomorrow this is just to remind folks that the models will be out 1 hour earlier from tomorrow, so for the 12z's GFS will start around 15:30 with ECM running from 18:00 to 19:00

 

......and the pub run coming out at 21.30.

[Duane S.]

A few of the gefs members continue to toy with the idea of a dominant trough east of the meridian dragging down some colder air with it towards the end of the first week of November, will be interesting to see if they are on to something.

[knocker]

The 06 GEFS anomaly still has the trough NW of the UK and eastern seaboard but significantly a ridge to the west of the UK. Thius slack pressure eastern Atlantic with a low to the west and above average temps. The jet at week ending the first is a very nondescript affair.

Edited October 25, 2014 by knocker

[Summer Sun]

Looks like a warm start to next week with temperatures widely in the high teens for England and wales some southern parts may manage the low 20's

 

 

By Tuesday its easy to see where the cooler air is given the huge contrast in temperatures, Scotland struggles to make double figures whilst England and wales see's temperatures in the high teens again maybe as high as 21c for one or two spots in the south

 

 

By Wednesday temperatures are lower for all with a drop of 7c to 10c widely for England and Wales

 

 

By the end of the week we have hints of milder air returning from the south west and its here where temperatures rise on Thursday towards the mid teens, 9c to 13c elsewhere for England and Wales

 

 

By Friday which is of course Halloween temperatures are back in the high teens for the south and low to mid teens for the rest of England and wales

 

 

Saturday again sees temperatures in the mid to high teens for the south and low to mid teens for the rest of England and wales

 

 

Monday afternoon sees a band of rain in NW Scotland

 

 

This slowly moves across the UK during the night and into Tuesday with the south and SE last to see it on Wednesday

 

[Ali1977]

Quite a few GFS Ens are showing WAA towards Greenland at T192, this producing some quite strong northerly winds..

Edited October 25, 2014 by Ali1977

[MR EXTREMES]

nice gap building on the gefs bit of eye candy if things were to progress.

ukmo is a north south split 

 

but even this could progress in the right direction.

Quite a few GFS Ens are showing a lot of WAA towards Greenland at T192, this producing some quite sting northerly winds..

there have been a few runs recently showing this i think its possibilty tbh.

[Yarmy]

Does anyone know if the models are still missing the snow and ice satellite data at the moment?

[knocker]

The GEFS 12Z anomaly persisting with the trough from the Pole south into Europe and the ridge to the west of the UK. Another trough Greenland to NE Canada. .Surface synopsis low south of Greenland and HP eastern Atlantic with slightly below average temps in the UK.

[Midlands Ice Age]

 

nice gap building on the gefs bit of eye candy if things were to progress.

ukmo is a north south split 

 

but even this could progress in the right direction.

there have been a few runs recently showing this i think its possibilty tbh.

 

In the case of the MO above it would I feel evolve into the GEFS control you have identified.

What happens afterwards might be quite good for a coldspell..... but its a long way off in fI.

[Cloud 10]

ECM teasing for a cold bonfire night perhaps?

 

 

Not a million miles away from the gefs mean posted above.

[radiohead]

ECM teasing for a cold bonfire night perhaps?

 

ECH1-240.GIF

 

Not a million miles away from the gefs mean posted above.

 

I think the main headline on that chart is something other than cold

 

[SMU]

So then as we approach November the patterns for the NH start to feedback differently, the Cold is expanding rapidly & with that the window of opportunity for snow in the UK starts to open.

 

The ECM & the JMA are starting to build a -NAO pattern at day 8-10. Its almost as if October is being ushered out so the calm Warm weather goes along with it.

 

In terms of Day 10 which one such outcome presents itself as we see a deep cross polar flow developing. Some points below.

 

 

In terms of Blocking we see a nice 1030 MB ridge over the pole- elevating the jet across that area scooping up plenty of cold air.

Also a concentrated area of higher Heights off the east coast of Canada heading into Southern Greenland.

The 'Anomalies' are great but the actual depth of the Highs aren't that significant, however they serve to distort the jet enough to move it into Areas its not accustomed to in November.

 

The Polar vortex is thoroughly 100% squashed over on the Russian & Siberian Side,however a breakaway area of energy is moving SSW across Svalbard. There is NO jet conformity to the norm & certainly a very negative zonal index V the norm, especially across the US & towards Greenland.

 

This is reflected in how stationary the Highs are in Quadrants 1 & 2 with little movement, & heights way above average,

All the action is reversed westwards out of Eastern Siberia towards Russia & beyond, Also in the mix is the UK starting to see the cold flex & some considerable snow building up for the Scottish Ski resorts at this early juncture.

 

All in all a jet stream being modelled which is inverse to the norm heading East to West, & it wont be long before that ripples & effects the UK-

 

S

[knocker]

I'm afraid I'm being a bit thick here as I don't follow what you mean by "All in all a jet stream being modelled which is inverse to the norm heading East to West, & it wont be long before that ripples & effects the UK"-

Edited October 25, 2014 by knocker

[Summer Sun]

ECM teasing for a cold bonfire night perhaps?

 

ECH1-240.GIF

 

Not a million miles away from the gefs mean posted above.

 

If that comes off most firework displays would be called off, doesn't look particularly cold for the south

 

 

Will be interesting to see if the ens gives it any support around 9:30

[Methuselah]

I'm afraid I'm being a bit thick here as I don't follow what you mean by "All in all a jet stream being modelled which is inverse to the norm heading East to West, & it wont be long before that ripples & effects the UK"-

I do hope that it 'effects [sic] the UK' faster than it did last year...

[SMU]

Hi Knocker its all about the jet -

 

Normalily is this:

 

http://modeles.meteociel.fr/modeles/reana/1993/archivesnh-1993-1-25-0-5.png where you see one continuous jet around the globe

 

ALL going one way.

 

Now look at the ECM

 

 

Its got a lot of peaks & troughs - Also the jet heading across the pole is the clue.

 

The reverse zonal flow around 75N is the key- look at the orange lines the MAIN jet is off to the south, however we have a returning Arm running all the across from Siberia across Kara & Svalbard towards The NW of Europe ( Mainly the extreme NW parts)
Hence cross polar flow.

 

With a jet so prone to buckling it wont be long before we see large scale cold feeds into mid lattitudes....

S
 

 

[knocker]

Steve

 

I understand what you are saying but isn't one leg indicated by the orange arm running counter to the wind vectors as indicated on the chart as they circulate around the upper low?

Edited October 25, 2014 by knocker

[SMU]

Maybe I did it quick.. I don't think so as my orange lines are identical to the chart below....

 

 

Heres probably the most famous cross polar flow showing the type of jet it delivered......

 

http://modeles.meteociel.fr/modeles/reana/1978/archivesnh-1978-12-31-0-5.png

 

S

[draztik]

ecm control days 9-14 / temp anom.

 

the control on the tease this evening.... however, the mean shows the opposite. Warmer than average for the UK & much of Europe into ext outlook...

[knocker]

Yes I can see what you are saying Steve but the cross polar flow still has to follow principles that dictate directional wind flows around upper lows and highs and thus the contour chart for that level. Anyway enough of that for now.

[Nouska]

Would an animation of the ECM 500mb anomalies help to display the points being looked at?

Unfortunately, free sites dont have the jet stream levels.

 

http://www.tropicaltidbits.com/analysis/models/ecmwf/2014102512/ecmwf_z500a_nhem.html

[Barry12]

More blocking again on the pub run...

 

Edited October 25, 2014 by Barry95

[Duane S.]

I see the NCEP MJO forecast is stilll out on its own regards going high amplified phase 8 / 1. Was doing something similar a week or so ago. Most others are going for a much more muted signal.Hopefully the GEFS is on to something because that could light the touchpaper for early to mid November...